The present invention relates to a method of controlling an injector for supplying fuel to an engine.
One example of the injector which is controllable by this invention is shown in FIG. 2. A valve body 30 is slidable in a valve housing 27, and the fuel is supplied through an injector hole 31 while the valve body 30 is moved rearwardly (right direction in FIG. 2).
In a conventional injector controlling method, the quantity of the fuel supplied from the injector during every reciprocating stroke of the valve body is controlled by a timing device. (The quantity of the fuel supplied per unit time is also varied by the frequency of the stroke.) In the following description, "fuel flow" means the quantity of fuel supplied with every valve body stroke.
When an engine is equipped with a supercharger turbine, the quantity of the fuel to be supplied with each suction stroke of the engine is increased during turbine operations. The injection valve open time cannot exceed the duration of suction stroke, therefore, the injector must be designed to be able to supply a large amount of fuel per unit time. Accordingly with such an injector, it may become very difficult to control the quantity of fuel flow with accuracy particularly in a relatively low fuel flow range, because of the difficulty of controlling the relatively short valve timing cycle with accuracy.
Therefore, it has been very difficult to adjust fuel flow with accuracy in a wide dynamic fuel flow range.